In recent years, the display resolution of a display device such as a home TV or a display for PC (personal computer) has been improved. For example, high resolution display devices with a display capability (display resolution) comparable to full high-vision (1080 pixels×1920 pixels) or higher have been developed. Thus, when an image content with standard definition (480 pixels×720 pixels) on a medium such as an existing DVD (Digital Versatile Disc) is displayed on the full screen of the above-mentioned high resolution display device, high resolution processing needs to be performed in order to increase the resolution of the images included in the image content up to the display resolution of the high resolution display device.
An enlargement processing using a linear filter is known as the current mainstream technique for high resolution processing. In addition, in recent years, a technique called super-resolution as a technique for high resolution processing has attracted attention, the super-resolution technique being capable of generating information with high resolution which does not exist in an input image (for example, see Non Patent Literature 1).